Electronic bus systems of the above-mentioned type, especially in the form of the so-called CAN bus system, are known from, for instance, private cars, in which the electronic control units are arranged in strategically selected positions in the car, as a rule in connection with a consumer, such as a bulb, which is controlled by the adjoining control unit. This control unit cooperates digitally via the bus wire with other equal control units in the car, the consumer connected thereto being normally supplied with current by a wire which extends in parallel with the bus wire. At the ends of the bus wire so-called terminating resistors are arranged, which serve to damp, at said ends, electric signals transmitted on the bus wire, such that no disturbing echoes arise.
A drawback of the above bus systems is that they have no redundancy, i.e. that even a small defect in the bus wire, for instance a fracture of a signal transmission wire included therein, or in a control unit connected to the signal transmission wire, may result in the function of the entire system being jeopardised. In a private car, the risk of such defects is relatively small thanks to the relatively short stretches of wire and the relatively protected arrangement. In larger vehicles, i.e. working vehicles such as fork lift trucks and lorries, particularly the length of the stretches of wires but also their exposed arrangement often contribute to the arising of such defects.